Hey folks,

I've recently had a minor problem with my AC and figured I'd see if anyone had some insights or possibly even a solution.

Problem:
I have a '04 MCS, 63K relatively easy miles, with Auto Climate control. On a warm, but not too hot, day recently, I noticed that it was taking longer than usual to cool the car down. Feeling the 4 ducts, and the center mounted top side duct, I noticed that the 2 passenger ducts were in fact blowing out refreshingly cold air and that the passenger half of the dash duct was also blowing cold air. The driver's side ducts were blowing strong, but the air was luke warm at best. An hour into my commute home, the cold air had balanced a bit, but it was still noticeably different between passenger and driver side. This phenomena has happened every day since, so it looks like what ever caused the problem in the first place is sticking.

In attempting to diagnose the problem, I've tried various combinations of the temperature setting, and recirculation, as well as the manual override on the vents. No impact.

Question:
Are there baffles in the AC system that regulate the air differently for the driver and passenger, and is it possible that the moveable baffle mechanics have died?

Anyone else have this problem?

Your thoughts would be most happily appreciated.

BB

 

Giving this a little bump in hopes someone may have an answer/opinion.

Thanks,

 

There is no separate air control door or baffle for driver and passenger. this is often a symptom or loose ductwork under the dash, missing seals on the air control doors themselves causing air to leak around them or sometimes even a case of evaporator icing on one side. The latter can be caused by low refrigerant charge or internal blockage in the case of manifolded evaporator cores. Since I barely have seen a MINI climate control stack removed for a car I dont know of the MINI has a manifolded or multipart parallel evaporator. For that matter, I cannot say if there is a provision for dual zone temp control (meaning separate blend doors) that would simply be tied together as one in our cars. If that was the case, one door could be sticking or warped and cause differing air outlet temps.

 

Hey Greatbear,

Thanks for responding to my question. I will definitely get under the dash to look for any loose connections. Generally, I'm tempted to lean towards your suggestion of a low refrigerant charge, because even on the passenger side, the air is not super cold (though I can't recall if it ever was or not).

As far as the multi-zone provision, I think your conclusion is right. I don't think there is one in the MINI. My thought was more along your comment about the blend door and that it may have stuck in such a way as to imbalance the air delivered to the cabin. Do you know if there's an easy way to access the blend door to see if something is awry ?

Thanks again.

If anyone else has some opinions on this, feel free. I never turn away a helpful suggestion.

Erick

 

As a side note: is the airflow itself sufficient? When is the last time you changed the cabin filter?

 

I have this same issue, so I'm interested in whatever you find out. I have the automatic climate control system as well.

 

I have been experiencing the same exact problem. I have a 05 s convertible. Someone please find out what is going on. I also have temperature control.

 

I've seen this condition fixed with a new expansion valve on a club member's MCS, odd (both the symptom and fix), but that corrected it.

 

Where is this expansion valve? Part number? Easy install?

 

No, installation is not easy http://www.lonestarminiclub.com/foru...read.php?t=571 . I replaced mine as a part of a total system refresh approach.

I was skeptical when I heard a faulty expansion valve caused the split effect cooling, but that was the part replaced on Isaac’s (Ike on NAM) service report. It would seem a valve controlling refrigerant volume would affect output from all the vents.

 

Excuse my ignorance, but where is the expansion valve in that picture? And I assume this means I have to evacuate the system first? And like you I dont see why that part would effect only the driver side vents. I assumed their must be flapper door in the venting system that is not opening properly, but no one has confirmed that yet or pin pointed it.

 

The expansion valve is the aluminum part with the brass plug located in the middle of this photo.

 

Thanks for the help K-huevo, I'll have to consider it if I have no other choice. But at this point it looks like it will end up being a spring time fix...

 

Hi guys,

After trying a few experiments over the summer, I'm still experiencing the problem. The balance of the cold/warm air does get better as the AC is running, but it takes a long time (more than 1 hour) to get the cabit cool, and the vents never do reach equilibrium. The passenger's side is always noticeably cooler than the driver's side. If it were a damper door, as I initially thought it would be, the balancing effect just wouldn't make sense, unless the door was hung up and very slowly releasing. Doesn't seem like a realistic explanation.

I'm a complete idiot when it comes to HVAC. Can someone with some experience explain exactly what the expansion valve does, and how it may be contributing to this problem ??? I would have thought that any component that's part of the refrigerant system would affect all 4 vents the same as the air passes over the same coolant, but I guess could be wrong, since, as I say, I'm an HVAC idiot .

Just one little update on my original post, the air on the passenger's side has been quite cold, and I think it's the correct temp. It's just the driver's side that's luke warm.

Erick

PS Thanks to K-Huevo for the pic and possible root cause

 

Not sure why only half of the vents are affected unless the ductwork is loose on half of the car. Looking at the diagram for the ducts on realoem that is probably the only way it makes sense IMHO.

Here is some more information that may be useful to diagnose the automatic A/C systems that BMW refers to as IHKA.

There is an on board diagnostic built into these systems, what follows is the procedure on how to access the on board diagnostics: The system has three modes. MODE1 - Shows any fault codes stored in the system. MODE2 - performs a calibration run of the doors that control mix and air distribution. MODE3 - provides for manual operation of the features.

Put the ignition in position 2 then press the OFF and blower PLUS buttons together for two seconds, the display will show a single streamer to represent MODE1. Each time the OFF button is pressed a different mode is displayed; to access any mode the AUTO button is pressed. In MODE2 the servo motors can be heard cycling from open to close position, this movement is detected by potentiometers built into the motor assembly. assuming the doors are still coupled to the motor shaft then the motors and doors will cycle and not give any errors, if the doors are not coupled to the servo shaft the system has no way of knowing and will cycle the motor end to end as reported by the sensor in the motor and everything will appear to be OK. Otherwise MODE1 will give any errors the system detects. There are 10 possible codes. I will post if anyone is interested.

 

Hey Frenchie,

I'm definitely interested in knowing these codes. I will be trying the diagnostic tonight, so it would be helpful to have the codes handy. Please post.

Thanks,
Erick

 

Code Description
01 Solar Sensor Fault
02 Interior Temp Sensor Fault
03 Heater Core Temp Sensor Fault
04 Air distribution servomotor feedback fault
05 Blend Flap Servomotor feedback fault
06 Blower switch minus fault
07 Blower switch plus fault
08 Interior sensor fan fault
09 Air distribution servomotor fault
10 Blend flap servomotor fault

The display will show either CA=Calibration Active; CC=Calibration Complete or FF=Fault.

Hope this helps!

 

There are two doors, one for the outside air, and the other for the A/C & heater core. The A/C blend door moves fore and aft so it can’t affect left & right distribution. According to a MINI tech, low refrigerant can also cause the split cooling symptom, which explains how a faulty (or dirty/clogged) expansion valve could play a part.

 

Hi guys,

I ran the AC diagnostics last night and it looks OK. Got an FF 00 code, which appears to mean everything is fine (at least as long as the motor's haven't gotten disconnected from the doors).

K-Huevo - I'm starting to think that this may be a charge related as you have pointed out in your last post. I guess I'm a bit disappointed that there's a leak in the system after only 4 years. Oh well.

Thanks Frenchie and K-Huevo for your insights and inputs.

E-

 

In addition to a low charge or blocked valve low air flow across the coil could cause it to freeze as well. Have you checked your carbon filter? Just a thought.

 

Hi Frenchie,

As part of my normal maintenance, I've changed the interior cabin filter. Is this the one you mean ?

The airflow inside the cabin from the four vents is symmetric, so it doesn't seem to be an airflow problem there.

E-

 

Here’s a helpful info link posted in a related thread http://www.aircondition.com/tech/cat...47%7DC-Basics/ .

One thing (of many) you could do is have the system serviced. The system will be pressure tested, refrigerant removed and system vacuumed, refrigerant recharged, the needed amount compared to the original recovered amount, and a dye & lubricant added to aid in detecting leaks. If additional refrigerant is needed then perhaps you have a leak. Something you can do before hand is to look for dirty/oily places on the refrigerant lines and connector flanges, that way if the servicing shop has a leak detector the suspect spots can be targeted. An A/C service person will need accurate details of the symptoms to help in diagnosis.

 

I've just dumped a bucket load of cash into my other car, so this may have to wait until the spring. Here in Mass, I won't be needing the AC for a while, so I can save up my pennies.

Thanks for the advice.
E-

 

Here is another thought; if the coil is iced over there should be a constant drip of water through the drain tube under the car long after the system has been switched of while the ice melts.

 

Thanks for the thought Frenchie. I don't think this applies to my situation because I have the problem as soon as I turn on the car. But I will keep an eye on this.

Thanks again,
Erick